metno-norway-weather

name

metno-norway-weather

description

Fetch and interpret Norwegian weather data from MET Norway's open APIs. Use when Codex needs forecasts, immediate precipitation nowcasts, subseasonal outlooks, tidal water forecasts, weather warnings, or sunrise and moon data for places in Norway, and the task should be solved with api.met.no products such as Locationforecast 2.0, Nowcast 2.0, Subseasonal 1.0, Tidalwater 1.1, MetAlerts 2.0, or Sunrise 3.0.

MET.no Norway Weather

Overview

Use this skill to choose the correct met.no product, build compliant requests, and interpret the results for Norway-focused weather tasks.

Prefer coordinates when they are already known. If the user gives a Norwegian street address, use the bundled helper's Kartverket geocoder via --address; it resolves official Matrikkelen addresses through the free Geonorge Adresse API before calling MET. For non-address place names, resolve to lat and lon first using local context or another approved geocoder, then call the MET API.

Choose The Product

• Use locationforecast/2.0 for general weather forecasts up to 9 days. Start with /compact unless the task needs percentile values or extra detail from /complete.
• Use nowcast/2.0 for the next 2 hours, especially if the user cares about immediate rain or snow in Norway. This product is radar-aware and updated every 5 minutes.
• Use subseasonal/1.0 for daily weather outlooks out to 21 days in the Nordic area. Prefer this when the user asks for a longer-range trend instead of a short forecast.
• Use tidalwater/1.1 for harbor-specific water level forecasts in Norway. Use this for storm-surge adjusted water levels, not for general ocean tide explanations.
• Use metalerts/2.0 for active warnings, warning history, or alert filtering by county, event, or coordinates.
• Use sunrise/3.0 for sunrise, sunset, solar noon, moonrise, moonset, and related solar or lunar timing.
• Do not use locationforecast or nowcast for aviation altitude forecasts. Their altitude parameter is ground elevation, not a flight level.

Follow MET.no Request Rules

• Send a unique, identifying User-Agent on live requests. Include an app or domain name and a contact address or URL.
• Use HTTPS only.
• Truncate lat and lon to at most 4 decimals before calling the API.
• Respect Expires and Last-Modified headers. Reuse cached results and prefer conditional requests with If-Modified-Since.
• Avoid synchronized polling. Spread repeated requests over time.
• Cache immutable resources aggressively. In particular, a MetAlerts CAP file should only be downloaded once per alert id.
• Prefer a backend proxy for browser and mobile use. MET warns against direct high-volume browser-to-API traffic, and custom-header CORS flows are not supported.

Workflow

1. Normalize the request. Determine whether the user wants a general forecast, a short-term precipitation answer, a 21-day outlook, a harbor water-level forecast, an alert lookup, or solar or lunar timing. Capture lat, lon, address, optional ground altitude, harbor name, language, and any date or archive period.

2. Choose the smallest useful product. Favor /compact for Locationforecast, /complete for Subseasonal, plain text for Tidalwater, and .json for MetAlerts unless the task explicitly needs XML or CAP details.

3. Use the bundled helper when fetching live data or building URLs. The script is at /workspace/skills/metno-norway-weather/scripts/metno_fetch.py. Use run_python_script to call it (see pattern below).

4. Interpret the response at the right level. Summarize what matters to the user instead of dumping raw JSON. Include timing, uncertainty, and any obvious caveats such as radar coverage limits or polar-night null values.

Use The Helper Script

Call run_python_script with a small wrapper. Example for a live forecast fetch:

import subprocess, sys
result = subprocess.run(
    [sys.executable,
     "/workspace/skills/metno-norway-weather/scripts/metno_fetch.py",
     "locationforecast", "--lat", "59.9139", "--lon", "10.7522",
     "--user-agent", "homeagent [e-mail]"],
    capture_output=True, text=True
)
print(result.stdout or result.stderr)

To inspect the URL without fetching (useful for debugging), add "--print-url" to the argument list.

Common invocations (replace coordinates and flags as needed):

• Locationforecast compact: ["locationforecast", "--lat", LAT, "--lon", LON, "--mode", "compact"]
• Locationforecast for a Norwegian address: ["locationforecast", "--address", ADDRESS, "--mode", "compact"]
• Nowcast: ["nowcast", "--lat", LAT, "--lon", LON]
• Subseasonal: ["subseasonal", "--lat", LAT, "--lon", LON]
• Geocode only: ["geocode", "--address", ADDRESS, "--limit", "3"]
• Tidalwater: ["tidalwater", "--harbor", HARBOR]
• Sunrise: ["sunrise", "--lat", LAT, "--lon", LON, "--date", DATE, "--offset", TZ_OFFSET]
• MetAlerts: ["metalerts", "--method", "current", "--format", "json", "--county", COUNTY_CODE] or ["metalerts", "--method", "current", "--format", "json", "--address", ADDRESS]

The script rounds coordinates to 4 decimals. Address lookups use Kartverket's https://ws.geonorge.no/adresser/v1/sok and return the first API-ranked match, so include postcode or municipality when an address may be ambiguous. Always pass --user-agent for live MET requests.

Interpret Common Responses

• For locationforecast and nowcast, inspect properties.timeseries. The current step is usually the first element. Use data.instant.details for the base values and next_1_hours, next_6_hours, or next_12_hours summaries when present.
• For subseasonal, expect daily GeoJSON forecast data with longer-horizon aggregates and percentiles. Summarize trend and spread, not single-hour precision.
• For tidalwater, parse the fixed-width plain text table and explain SURGE, TIDE, and TOTAL in meters above mean sea level. The timestamps are UTC.
• Treat symbol_code as a presentation-ready weather icon key. Do not call Sunrise just to decide whether icons should use day or night variants.
• For metalerts JSON, prefer summarizing severity, event type, affected area, onset, expiry, and any incidentName.
• For sunrise, expect GeoJSON and remember that sunrise, sunset, moonrise, or moonset may be null near polar night or midnight sun conditions.

Read The Reference File When Needed

Read /workspace/skills/metno-norway-weather/references/metno-api-reference.md using run_bash_command(["cat", "skills/metno-norway-weather/references/metno-api-reference.md"]) for:

• endpoint and parameter details
• product-specific caveats
• request examples
• direct links to the official documentation